Author Topic: SNC building test schedule for Dream Chaser – Dryden Drop Tests upcoming  (Read 42082 times)

Offline LaunchedIn68

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Can anyone tell me why the WK is no longer an option for the DC drop tests? I must have missed that part.

Reportedly over concerns that use of the vehicle will delay flight testing of SpaceShipTwo. They also had concerns about potential damage to the carrier aircraft
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Offline Jason1701

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Can anyone tell me why the WK is no longer an option for the DC drop tests? I must have missed that part.

Reportedly over concerns that use of the vehicle will delay flight testing of SpaceShipTwo. They also had concerns about potential damage to the carrier aircraft

Could they possibly see DC as an airlaunched hybrid-powered competitor to SS2?

Offline Elmar Moelzer

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I dont quite get the concern about delaying SS2 testing. The SS2 tests are still very infrequent and I doubt that the WK2 will be used fully by them. I might be underestimating the amount of service hours it needs, though.
I would understand concerns about the DC being able to damage the WK2. That would however be in stark contrast about the versatility VG claimed for the WK2 in the beginning of the development (it was advertised as being useful for just this thing) of the WK2 SS2 system.
Still, with only one WK2 being currently operational, even a freak accident damaging it would indeed delay SS2 testing. So maybe that is their reasoning behind that?
 
Could they possibly see DC as an airlaunched hybrid-powered competitor to SS2?

IIRC, the suborbital version of the DC was not meant to be airlaunched, but would have launched vertically like the X33.
Last time I saw that was a long time ago though and it might have changed since then.
Anyway, this does sound like a plausible explanation to me. But then, I dont think that SNC would care much about flying the DC suborbitally, if they were selected for commercial crew. I also think that it would need some modifications for that (IIRC, I would have needed more of the same hybrid engines, but that might have changed as well). So not letting them do the drop tests might actually be counterproductive, since it would reduce SNCs chances for commercial crew and thus would make a suborbital DC more likely. Granted, this is massive speculation on my side and I may be wrong here (it is still fun to speculate though).

Offline Lee Jay

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Gliders are frequently towed.  If the Dream Chaser can take off on its wheels then a fast, high flying aircraft may be able to get it into the air.

Yeah, gonna take more than a Piper Pawnee to tow that glider!

DC has no front landing gear (just a skid) and a normal landing speed above 190 knots.  I'm not sure it could be towed given those particular attributes.

Offline Rocket Science

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Gliders are frequently towed.  If the Dream Chaser can take off on its wheels then a fast, high flying aircraft may be able to get it into the air.

Yeah, gonna take more than a Piper Pawnee to tow that glider!

DC has no front landing gear (just a skid) and a normal landing speed above 190 knots.  I'm not sure it could be towed given those particular attributes.
They could use a dolly under the skid that remains on the ground or replace the nose skid for a conventional gear for this test using air tow and ignite motors to gain altitude and airspeed. Of course they will need a retract mechanism. An aircraft like the C-17 could get the job done to air tow DC.
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Offline Prober

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Is this going to be a full size DC?

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Offline JAFO

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Recall that in December 1997-February 1998 NASA sucessfully towed a F-106 behind a C-141 in the Eclipse Project. http://www.nasa.gov/centers/dryden/about/Organizations/Technology/Facts/TF-2004-02-DFRC.html

May not be practical for DC since the loads on the structure would be different for a nose tow attachment than the top of the fuselage mount.


Trivial pursuit: one of the test pilots of the F-106 was Mark "Forger" Stuckey, now a pilot on SS2.
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Offline Rocket Science

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Recall that in December 1997-February 1998 NASA sucessfully towed a F-106 behind a C-141 in the Eclipse Project. http://www.nasa.gov/centers/dryden/about/Organizations/Technology/Facts/TF-2004-02-DFRC.html

May not be practical for DC since the loads on the structure would be different for a nose tow attachment than the top of the fuselage mount.


Trivial pursuit: one of the test pilots of the F-106 was Mark "Forger" Stuckey, now a pilot on SS2.

Yup, If SNC was to go this way with air tow they would have to be sensitive to turbulence behind to tow aircraft. The L/D of the DC and aero properties being quite a bit different than the QF-106 it could be simmed and tested in a wind tunnel. Another is to see if DC can get out of ground effect on takeoff roll. You can imploy RATO bottles mounted along the sides to assist. It could even ground light the Hybrid motors and take off on its own then. If you want a fancy way to ensure launch you could build a “ski jump” ramp as is used on the British class aircraft carriers for the Harrier. Or you could ignite the motors after drop from SkyCrane and climb to test altitude and airspeed. Heck we did "zero length launch" in the 1950's. The point I am trying to make is that there are always alternatives if you are creative in you thinking...

http://aviationtrivia.blogspot.ca/2010/04/development-of-bae-sea-harrier-frs.html

http://upload.wikimedia.org/wikipedia/commons/thumb/d/de/YAV-8B_Harrier_testing_a_ski_jump.jpg/746px-YAV-8B_Harrier_testing_a_ski_jump.jpg


http://www.youtube.com/watch?feature=endscreen&v=oImq1glnOds&NR=1
« Last Edit: 12/15/2012 12:33 PM by Rocket Science »
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Offline Elmar Moelzer

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Recall that in December 1997-February 1998 NASA sucessfully towed a F-106 behind a C-141 in the Eclipse Project. http://www.nasa.gov/centers/dryden/about/Organizations/Technology/Facts/TF-2004-02-DFRC.html

May not be practical for DC since the loads on the structure would be different for a nose tow attachment than the top of the fuselage mount.


Trivial pursuit: one of the test pilots of the F-106 was Mark "Forger" Stuckey, now a pilot on SS2.

The Kelly Eclipse was meant to have much larger wings than that. I dont think the DC is a good enough glider to be towed, but I may be wrong here.

Offline Rocket Science

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Recall that in December 1997-February 1998 NASA sucessfully towed a F-106 behind a C-141 in the Eclipse Project. http://www.nasa.gov/centers/dryden/about/Organizations/Technology/Facts/TF-2004-02-DFRC.html

May not be practical for DC since the loads on the structure would be different for a nose tow attachment than the top of the fuselage mount.


Trivial pursuit: one of the test pilots of the F-106 was Mark "Forger" Stuckey, now a pilot on SS2.

The Kelly Eclipse was meant to have much larger wings than that. I dont think the DC is a good enough glider to be towed, but I may be wrong here.
M2-F1 was towed behind a C-47 and a car (Pontiac) no problem. ;)

http://www.nasa.gov/topics/history/M2_F1.html

http://www.redorbit.com/news/space/1526597/the_m2f1_forefather_to_the_space_shuttle/
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Offline Elmar Moelzer

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Not sure how comparable this prototype is with the DC, but I guess towing might be an option after all (if they dont run into stability problems).

Offline Rocket Science

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Not sure how comparable this prototype is with the DC, but I guess towing might be an option after all (if they dont run into stability problems).
If you are curious about lifting bodies have a look at my thread here...

http://forum.nasaspaceflight.com/index.php?topic=29126.0
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Online john smith 19

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If you are curious about lifting bodies have a look at my thread here...

http://forum.nasaspaceflight.com/index.php?topic=29126.0
The M1F2 was a plywood over welded metal tubing design mostly to demonstrate it could glide at all.

BTW I thought that DC is moving to "skids" or metal brushes rather than wheels. I'd guess the friction would be difficult for a rolling towed takeoff.

A high(ish) altitude drop with the hybrid rocket to get the rest of the altitude and speed needed seems the most plausible way to widen the envelope if WK2 is not available I think DC is small enough to be dropped out of a big carrier aircraft but that's a whole different area to explore.

Thanks for the zero length launch video. I would not have believed they ever managed it with a crewed vehicle, although I was aware some of the cruise missile designs of the 50s were baselined with it. 
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Offline Rocket Science

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If you are curious about lifting bodies have a look at my thread here...

http://forum.nasaspaceflight.com/index.php?topic=29126.0
The M1F2 was a plywood over welded metal tubing design mostly to demonstrate it could glide at all.

BTW I thought that DC is moving to "skids" or metal brushes rather than wheels. I'd guess the friction would be difficult for a rolling towed takeoff.

A high(ish) altitude drop with the hybrid rocket to get the rest of the altitude and speed needed seems the most plausible way to widen the envelope if WK2 is not available I think DC is small enough to be dropped out of a big carrier aircraft but that's a whole different area to explore.

Thanks for the zero length launch video. I would not have believed they ever managed it with a crewed vehicle, although I was aware some of the cruise missile designs of the 50s were baselined with it. 
There is no cargo door large enough that I have found yet to release from... DC is using a skid for the nose gear for which they could use a dolly under. Or keep all the gear retracted and use a three wheeled dolly that could be dropped after takeoff, like was done with the Messerschmitt Me-163 Komet, (which used a two wheel one).  A rocket booster can even be mounted in a dolly and then the Hybrid motors could be ignited for climb out. Once again always possibilities...  I really see no showstoppers with this program...



« Last Edit: 12/16/2012 12:06 PM by Rocket Science »
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Offline mr. mark

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Looks like the Dreamchaser project is starting to hit some unexpected realities. Wonder how soon until the Stratolaunch lifter is ready? Several years away?

Offline Rocket Science

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Looks like the Dreamchaser project is starting to hit some unexpected realities. Wonder how soon until the Stratolaunch lifter is ready? Several years away?
DC will be on orbit before it if ever completed...
« Last Edit: 12/16/2012 12:04 PM by Rocket Science »
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Offline mr. mark

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In orbit? Looks like they are having trouble just getting Dreamchaser off the ground for this droptest. Might be the Spruce Goose of spaceflight. As for a rocket assisted first test flight, I would say that is very unrealistic with a lifting body design.

Offline Rocket Science

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In orbit? Looks like they are having trouble just getting Dreamchaser off the ground for this droptest. Might be the Spruce Goose of spaceflight. As for a rocket assisted first test flight, I would say that is very unrealistic with a lifting body design.
It is not a technical or design problem with DC... The problem is with Scaled, ask them for motives...
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Offline QuantumG

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It is not a technical or design problem with DC... The problem is with Scaled, ask them for motives...

What's Scaled got to do with it?

VG owns WK2.
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Offline Rocket Science

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It is not a technical or design problem with DC... The problem is with Scaled, ask them for motives...

What's Scaled got to do with it?

VG owns WK2.

Did not Northrop Grumman buy scaled? If you say VG owns WK2 in particular, I’ll take you at word Trent...

Edit to add: I just checked this, not that I don't trust you... ;D

http://www.militaryaerospace.com/articles/2012/10/virgin-scaled.html
http://www.parabolicarc.com/2012/10/06/virgin-galactic-takes-full-ownership-of-the-spaceship-company/
http://www.businesswire.com/news/home/20121005005907/en/Virgin-Galactic-Acquires-Full-Ownership-Spaceship-Company

Me smells Sir Richard me thinks... ::)
« Last Edit: 12/16/2012 01:33 PM by Rocket Science »
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